This invention relates to a printer as a typewriter, a computer terminal, etc., which has a platen and support frame means such as a carriage movable relative to the platen in a printing direction, and in which a type-wheel cassette accommodating a type-wheel is removably mounted on the support frame means, the type-wheel in the type-wheel cassette is rotated by type selection means mounted on the support frame means, and a selected type is hammered at a printing position by a printing hammer mounted on the support frame means to effect printing, and more particularly, to a type-wheel cassette positioner for such a printer.
As a printer of this type, there is known a typewriter with a carriage movable along a printing line, the carriage being provided with a paper guide member forming a paper passage space with a platen, an ink ribbon guide member forming an ink ribbon running space with the paper guide member, a type-wheel cassette accommodating a type-wheel, type selection means disposed on the side of the type-wheel cassette opposite the platen and coupled to the type-wheel in a state penetrating the center of rotation of the type-wheel cassette for selecting a given type by rotating the type-wheel, and a printing hammer for hammering a selected type against the platen. The ink ribbon guide member is mounted on the paper guide member to define the ink ribbon running space between the two. The type-wheel in the type-wheel cassette is coupled to the selection means to determine the position of the type-wheel cassette. The size of the paper passage space is adjusted by adjusting the mounting position of the paper guide member. The size of the gap between the type-wheel and type-wheel cassette inner wall is determined as the type-wheel cassette is urged by the leaf spring toward the paper guide member from the side of the type selection means.
With this prior art printer structure, however, the position of the mounted type-wheel cassette is subject to variation due to adjustment of the mounting position of the paper guide member. Therefore, the size of the gap between the ink ribbon guide member and type-wheel, and the paper passage space are subject to variations. This means that adjustment of the individual gaps noted above to appropriate sizes in a narrow space between the printing hammer and platen requires adjustment of the individual components at the time of the mounting and assembly of these components. The adjustment, therefore, is very cumbersome and time-consuming.